Ten years, 18 films and over NZ$19 billion dollars in box office revenue - the Marvel Cinematic Universe has turned superheroes into superstars and their stories into movie folklore.

Marvel now brings all their Avengers plus hangers-on together for a gargantuan superhero mash-up and the wait for Avengers: Infinity War is official over.

The monumental conglomeration of superheroes has been treading purple carpets everywhere to press the fan flesh and to front for press.

At an Infinity War media event in Singapore, Robert Downey Jr was singing the praises of New Zealand filmmaker Taika Waititi and his Marvel movie.

"I thought Thor: Ragnarok was so mindblowing. This Taika Waititi guy, to me, he's an assassin… so brilliant," said the man who plays Iron Man.

It's a sentiment shared by Doctor Strange actor Benedict Cumberbatch.

"It was so refreshing, and I think that was the most freedom they've given a director," he said of Ragnarok.

"It unnerved them a little bit and rightfully so, as it was such a massive kind of gear-change. It was brilliant."

Bringing all the superhero strands of all 18 films together into two grand finales fell to the Russo Brothers, Anthony and Joe.

One of their biggest challenges was how to make Waititi's rather different Thor work in Infinity War.

"We stayed in close contact with Taika - not only because we love him and he's hilarious and a lot of fun to be around - but because we had to," says Joe.

"We knew he was taking the character in a whole new direction, and it was important for us as we were literally rolling cameras at the same time to understand where he was going. We certainly have our own interpretation of the character in the film and again, that's what people like about it.

"But there are shadings of what Taika was doing in Ragnarok with the character. He's certainly much funnier in Infinity War than he was in Ultron and the first Avengers."

Cumberbatch says it's the studio's ability to unpack big themes within the context of the blockbuster which gives them enormous power, and never more so than right now.

"This one is about United We Stand, Divided We Fall," he says.

"It's about the power of collective. We're living through an era where this is very, very potent I think, with the hashtag #MeToo and #Times Up and also what the kids are doing in America about gun control and fighting for their future and their rights, and they've been very savvy and brilliant as collective."